Binocular viewing device for stereophotogrammetric instruments



March '7, 1939. H. GLiLDBRANDSEN 2,149,601

BINOCULAR VIEWING DEVICE FOR STEREOPHOTOGRAMMETRIC INSTRUMENTS Filed Dec. 31, 195'! In ven/or:

Patented Mar. 7, 1939 UNITED STATES BINOCULAR VIEWING DEVICE FOR STEREO- PHOTOGRAMMETRIG INSTRUMENTS Henry Guldbrandsen. Jena, Germany, assignmto the iii-m Carl zeisaJena, Germany Application December 31, 1931,. Serial No. 182,886 In Germany January 18,1937

2'Clalms.

I have filed an application in Germany. January 18, 1937.

The invention concerns a binocular viewin device to be used in stereophotogrammetric measuring instruments and in each half of which a system of mirrors is so displaceable parallel to the base line that all mirrors participating in this displacement take part, in each of two difjerent positions, in the imaging of one of the two elements of a stereoscopic image of an object, the observer being presented the view of an orthoscopic stereoscopic image in the one, and the view of a pseudoscopic stereoscopic image in the other of the said two positions.

To avoid in a viewing device of this kind the displacement of the mirror systems from the one position to the other entailing a change in the length of the ray pencils in the convergent path of the rays, the object side of the mirror system of each half of the device is provided according to the invention with a lens system which participates in the displacements of this mirror system and whose focal length is the same as the distance of its internal perspective centre from the image plane of the corresponding eye-piece, this distance being measured along the optical axis.

Figures 1 and 2 of the accompanying drawing, which illustrate the invention, represent part of a binocular viewing device for stereophotogrammetric plotting instruments in a section through the optical axis of this device, the displaceable system of optical members assuming two different positions. Figure 1 shows the position in which the observer is offered the view of an orthoscopic stereoscopic image, and Figure 2 the position in which the observer is offered the view of a pseudoscopic stereoscopic image.

To a base plate i are fixed the two eye-pieces 2 and 3 of the binocular viewing device, whose image planes 4 and 5 coincide. Two spindles 6 and I are so mounted on the base plate I that their axes are at right angles to those of the eyepieces 2 and 3. The spindle I can be rotated about its axis by means of a milled head 8. This spindle 1 has a right-handed thread 9 and a left-handed thread [0. The internally threaded part l2 a plate II is in mesh with the righthanded thread 9, and the internally threaded the lefthanded thread It. The displaceable along the spindle S. The plate H carries a lens [5, whose axis is parallel to the axes of the spindles 6 and 1 and lies in the plane containing the axes of the eye-pieces 2 and 8,

and three prisms l8, l1 and [8, each of which deflects the axis of the lens l within the said plane through 90, so that this axis is parallel to the axes of the eye-pieces 2 and 8 when it emanates from the prism 18. The lens (5 has a 5 focal length which is the same as the distance of its internal perspective centre H from the image planes 4 and 5 of the eye-pieces I and 3, this distance being measured along the optical axis. The focal length or the lens l5 corresponds, l0 accordingly, to the sum of the distances designated a, b, c and d in Figure 1. The plate It carries a lens 19, whose axis coincides with that of the lens l5, and three prisms 20, II and 22, each of which deflects the axis of the lens l9 within the said plane through 90, so that this axis is parallel to the axes of the eye-pieces 1 and 3 when it emanates from the prism 22. The lens i9 has a focal length which is the same as that of the lens IS. The distance oi the internal perspective centre H of the lens [8 from the image planes 4 and 5 of the eye-pieces 2 and 3, which is measured along the optical axis and composed of the distances 11,", b, c and d, is accordingly, the same as the distance oi the internal perspective centre H of the lens l5 from the said image planes 4 and 5, which is measured along the optical axis. To the spindle 'l are fixed stops 23, 24 and 25 for interrupting the displacements of the plates ii and i3 in two so directions. Figure 1 shows those extreme positions of the plates H and [3 in which the rays emanating from the lenses l5 and 19 are directed to the eye-pieces 2 and 3, respectively. In the other extreme positions of the plates H and i3, which are shown in Figure 2, the rays emanating from the lenses. l5 and iii are directed to the eyepieces 3 and 2, respectively.

I claim:

In a device for viewing stereoscopic images, a base plate, two eye-pieces, two optical systems mounted on said base plate, the optical axes of said eye-pieces being parallel to each other, each of said optical systems comprising a mirror sys tem and a lens system,'the focal plane of each 45 of said optical systems coinciding with the image plane of said eye-pieces, each of said optical systems being displaceable relatively to said base plate along a line intersecting the said optical axes at right angles, and means for displacing 5 each of said optical systems so as to make each optical system coact with either of said two eyepieces.

2. In a device for a base plate, two eye-pieces,

viewing stereoscopic images.

two carriers mounted on said base plate, the optical axes of said eyepieces being parallel to each other, two optical systems, each of said optical systems ed to one of said carriers. each of said optical systems comprising a mirror system and a lens system, the focal plane of each of said optical systems coinciding with the image plane oi said eye-pieces, each of said carriers being displaceable relatively to said base plate along a line intersecting the said opticai axes at right angles, means for displacing each of said carriers so as to make each optical system coact with either of said two eye-pieces. and means for so coupling said carriers that displacing the one carrier entails a corresponding reverse displacement of the other carrier.

HENRY GUIDBRANDSEII. 

